A stock has returns of 18 percent, 15 percent, -21 percent, and 6 percent for the past four years. Based on this information, what is the 95 percent probability range of returns for any one given year?
a. -31.00 to 40.00 percent
b. -47.68 to 54.68 percent
c. -71.73 to 71.73 percent
d. -24.60 to 31.80 percent
e. -13.56 to 20.56 percent